Mattress



FIG. 1 is a perspective view of the mattress showing my design;

FIG. 2 is a top plan view; and

FIG. 3 is a side elevational view, any of the other side views being the same.

The bottom of the mattress is flat and unornamented.

The mattress is shown broken away to indicate both indeterminate length and width. 

The ornamental design for a mattress, as shown and described. 